Grace Design m502, 1 Channel Optocompressor, same circuit as model Grace Design m102, Input and Output Gain, 3-way witch (-10dB to +10dB), Threshhold (+15 to -15), Attack (3ms - 200ms), Release (0,03s - 3s), Ratio (1:1 to 12:1, continuously variable), Stereolink + Sidechain per Jumper configurable, Gainreduction LED Meter, Signal+Peak Clip LED, Bypass, Format: API Series 500 Rack